1. Field of the Invention
The present invention relates, in general, to structures using lenticular lens materials or sheets to produce images, and, more particularly, to plastic cups, containers, or other objects and methods of making such objects that have a lenticular material integral with a clear outer wall(s) and an inner label insert with a printed image or series of image strips that is bonded and sealed to an inner surface of the container for viewing through the lenticular material.
2. Relevant Background
Products, such as containers and cards, that provide multiple images or motion to an image are appearing everywhere and are used for marketing everything from sports products, to recently released movies, to financial and identification products. Motion or image products use a special technology called lenticular printing that typically takes a batch of images and prints alternating strips of each image on the back of a transparent plastic sheet. The plastic sheet has a series of curved ridges called lenticules or lenticular lenses. When light passes through the plastic sheet, it is reflected from smooth white paper or plastic under the transparent plastic sheet. The returning light passes through the printed image strips and the lenticules are made in such a way as to refract the returning light at a specific angle and to magnify the image. The printed image strips need to be aligned accurately so that all the strips for a particular image (i.e., one in a series of still images that are used to make up a moving image) are refracted to the same point or are visible from a particular viewing angle. Because of the refraction and magnification, the viewer sees a single, complete image and as the viewer changes their line of sight, different image strips are seen as a series of complete images. In this manner, dozens of images in very tiny image strips can be combined to provide numerous images and even a few seconds of smooth video or animation. While the technology continues to improve and is more widely available, several manufacturing problems and associated costs have generally blocked widespread adoption of lenticular imaging within retail and marketing products.
Containers and cups fabricated from plastic are used extensively for goods ranging from water, alcoholic beverages, and soda pop and other beverages to soap and other household products. Billions of such containers and cups are produced each year typically using blow mold or injection molding technologies. The marketing and packaging industry continually struggles to meet two important and, often competing, goals: producing attention-getting, attractive containers to enhance marketing of the product inside the container and controlling material and production costs of the container while meeting government standards for safety (such as, in the United States, Federal Drug Administration standards for containers and cups). Eye catching graphics in packaging can play a large part at the retail level in making a product appealing to consumers. In the packaging industry, there are a variety of techniques that can provide informational graphics as well as illustrative or “eye appeal” graphics that include one color or use more elaborate multi-color graphics or photographs. More elaborate graphics are often produced with lenticular graphic labels using 3-dimensional (3D) and animation. Lenticular lens material is used in the marketing and packaging industries for creating promotional material with appealing graphics and typically involves producing a sheet of lenticular lens material and adhesively attaching the lenticular lens material to a separately produced object for display.
The production of lenticular lenses is well known and described in detail in a number of U.S. patents, including U.S. Pat. No. 5,967,032 to Bravenec et al. In general, the production process includes selecting segments from visual images to create a desired visual effect and interlacing the segments (i.e., planning the layout of the numerous images). Lenticular lenses or lens sheets are then mapped to the interlaced or planned segments or sets of image strips, and the lenticular lenses are fabricated according to this mapping. The lenticular lenses generally include a transparent web that has a flat side or layer and a side with optical ridges and grooves formed by lenticules (i.e., lenses) arranged side-by-side with the lenticules or optical ridges extending parallel to each other the length of the transparent web. To provide the unique visual effects, ink (e.g., four color ink) is applied to or printed directly in thin image strips on the flat side of the transparent web to form a thin ink layer, which is then viewable through the transparent web of optical ridges. The density or number of the lenticules (i.e., the lenticules per inch (LPI)), the thickness of the entire lenticular material, and other physical parameters (such as the diameter of the container or bend of the lenticular material) have to be carefully matched with the printed image to achieve a desired result, with the accuracy required for printing and then registering the images with the lenticules increasing directly with increased LPI, decreased thickness, and decreased container diameter.
While these lenticular lens materials provide excellent visual effects, the use of adhesives and other attachment methods has not proven effective in producing high quality, long-lasting, and inexpensive plastic products. Because attaching the lenticular lens material after producing the container is inefficient and relatively expensive, the plastic manufacturing industry is continually searching for methods for attaching the lenticular lens material to plastic cups or containers as part of the cup or container manufacturing process. To date, the plastic manufacturing industry has only had limited success in overcoming the problems associated with using common lenticular lens material as part of standard plastic fabrication processes. The problems arise because plastic fabrication generally includes processes such as injection molding that involve heating raw plastic materials to a relatively high temperature (e.g., 400 to 500° F. or hotter) and then injecting the fluid plastic into a mold with the shape of the desired plastic object or by otherwise processing the molten plastic. The ink or ink layer has a chemistry that does not stay intact when the ink is heated to these high temperatures, and the image is destroyed or at least significantly altered.
Additionally, the design and manufacturing of the plastic cup or container is often limited as the lenticular material and image generally has to be placed on the external surfaces of a container or cup so that the inside of the container is kept free from compounds (such as compounds that are found in most plastic adhesives) that are regulated by governments as being potentially dangerous if consumed. Further, the use of these graphic techniques is often rejected by the retail industry due to its high cost per container. The lenticular lens labels are typically costly, e.g., nearly double the cost of the other container or cup material. The manufacturing and/or assembly processes are also expensive. For example, in-mold labeling automation equipment is a very large capital expense (e.g., up to and over $100,000 in US dollars for an injection molding machine), which also makes is problematic for planning for capacities and periodic large orders. Hence, these costs can drive margins and capital paybacks to a point that makes it difficult to justify addition of lenticular imagery based on a cost-benefit analysis, e.g., the additional customer attention and increased sales are typically not offset by the reduced profit or margin on each product sale. In many industries, such as the entertainment industry, images for including on a label are not approved or released until a short time before the products are needed, such as immediately before a movie release date. Current manufacturing techniques require manufacturing of the containers along with the lenticular labels such that stocks cannot be produced prior to the production of the labels with the approved image sets. The challenge continues to be to create eye-catching graphics or packaging at a very low cost or even with a cost that is similar to packaging already used in present products.
Also, there has been a limitation in achievable imaging quality because of limitations in the thickness of the lenticular lens systems and printed image (i.e., existing labels). This limitation is seen most clearly in containers and cups manufactured using injection in-mold technology. Generally, as the thickness of the lenticular lenses increases, the power of the lenses increases, which results in enhanced graphic imagery. Unfortunately, the use of labels that combine lenticular material with layers containing printed images typically cannot exceed a relatively thin maximum thickness that is thinner than desired for obtaining high quality imagery. For example, combined lens and image thickness for in-mold labels typically has been less than about 20 mils for plastic cups. This thickness limitation is imposed because thicker plastic labels are difficult to manipulate manually or with robotics due to the stiffness and memory of the label that resist bending and insertion or attachment of the label about the exterior wall of the cup. The memory of the installed or attached label may even cause the finished cup to lose its circular cross sectional shape as the label attempts to return to its original flat shape, i.e., the cup becomes nearly oval in shape. Additionally, thicker labels have proven to be more expensive to manufacture due to material costs and due to processing costs. Further, the wall thickness of the cup or container may be diminished to provide a relatively consistent thickness at locations with a label and without a label, which can lead to structural integrity problems and leaking.
Hence, there remains a need for a method of manufacturing plastic cups and other containers having improved motion imagery or multiple images produced by lenticular material or lenticular lenses combined with a series of printed image strips. Preferably, cups or containers produced according to such method would be less expensive to produce facilitating adoption of lenticular printing in producing a variety of price sensitive products, including plastic cups for marketing entertainment products, events, and services. Additionally, such a manufacturing method would be highly scaleable to support tight production schedules by allowing portions of such cups or containers to be fabricated separately and prior to a final design for an image to be provided on the printed image strips.